Gearing for power transmissions



Nov. 25, 1952 E, WOYDT 2,618,988

GEARING FOR POWER TRANSMISSIONS Filed Dec. 15, 1949 2 SHEETS- SHEET 1 Ms 447 M@ Ms l Il. L 4 4m m Il) 414 r., i--l A02. Q ,mi M4 41a fr )LI H LL r LLL L '45e A03 9o -91 .-p 'T' HTM/MMS 4NOV. 25, 1952 E WOYDT 2,618,988

GEARING FOR POWER TRANSMISSIONS Filed Deo. l5, 1949 2 SHEETS- SHEET 2 MB M7 M@ M5 B ,Fon/@ wa 'YDT Patented Nov. 25, 1952 UNITED STATES PTEN FFME Application December 15, 1949, Serial No. 133,142 In Germany December 20, 1948 7 Claims.

This invention concerns iniinitely variable gears.

It is an object of the invention to connect an infinitely variable hydraulic transmission to a system of change gears in such a manner that a large speed range will be obtained with innite variation within that range using infinitely variable hydraulic transmissions having a small adjusting range only.

For this purpose the speed range of the hydraulic transmissions corresponds at least to the largest stage progression of the change gearing in such a manner, that, by engaging one stage of the change gearing, in conjunction with correspondingly high gear ratio of the hydraulic transmission a speed will be obtained at the driven shaft which is equal to that obtained when the next higher stage of the change gearing is engaged in conjunction with a correspondingly low gear ratio of the hydraulic transmission.

In such a transmission the intervals between the successive change gear ratios are of equal amount and each corresponds to the adjusting range of the hydraulic transmission. Also according to the invention two or more variable hydraulic transmission systems may be provided to overcome very high change gear ratio intervals, the total adjusting range being at least equal to the highest interval in the change gearing. v

According to the invention the means for the shifting of the change gearing is inter-connected with the means for the adjustment of the hydraulic transmission system in such a manner that by engaging a higher ratio of change gearing a reduction in the transmission ratio of the hydraulic system is effected, equal in extent to the increase of the change gear ratio. Thereby the speed ratio from the drive part to the driven part will be exactly the same immediately after the gear shifting as it Was before. Such an operation may be effected, for example, by having a control shaft carrying a cam which is arranged to actuate the innitely variable hydraulic transmission system. A second cam or an interrupted gear is synchronised to engage the next higher change gear ratio, the engagement being complete when the reduction of the hydraulic ratio is accomplished. However, in such construction it is necessary to incorporate a clutch to interrupt the power circuit temporarily.

The invention will be described further by way of example with reference to the accompanying drawings in which;

Fig. 1 is a schematic view of an entire transmission unit;

Figs. 2 and 3 are side views of the cam and of the gear segment;

Fig. la is a schematic view of the transmission unit shown in Fig. 1, when in first engagement position. Figs. 2a and 3a are side views of the cam and gear segment when in first engagement position.

In Fig. l, the innitely variable part 9| of the unit is driven through the driving shaft lill by means of the gears H32 and l3. The supply and discharge of the fluid to the part 9| is effected through the hollow shafts 90, 92, IB? and through the pipes |35 and |33 from or to a container respectively. The casing of the part Sl is secured against rotation at |35. Part 9| may be a hydrostatic fluid drive unit of the type shown and described in Patent No. 2,256,324 and Patent No. 2,255,963. The drive continues to run by means of the shafts 92 and lill and the gears It, |63 and |09. A second gear H9 mounted on the driving shaft lill meshes with the gear l I8 of the countershaft l l1 which carries also the two gears l I5 and H5. Movably arranged on the driven shaft llfi, but secured by aid of keys against relative rotation therewith, is the hollow shaft H3 on which the gears lll, lll and ll2 are mounted. The said hollow shaft can be displaced by means of the forked lever l23 fixed on the threaded rod lZl. The gear |22 is disposed by its internally threaded hub on the externally threaded rod |2| in such a manner that the latter will be displaced when the gear |22 is rotated. A control shaft |25 is journalled at |25 and |33 and is rotatable by means of the cranked handle |32 whereby the infinitely variable part SI may be controlled by means of a spring-loaded adjustable pin 9i' the end of which bears on the periphery of cam disc l2'la, also on shaft |25. A gear having an interrupted periphery ld, lll, as shown in Fig. 3, is also fixed on the control shaft |25. The gear segments |24 are synchronised to engage with the gear |22 when the pin al engages the faces |29 or l3| (Fig. 2). Owing to the position of the control shaft according to Fig. 2 the cylindrical cam section |29 has just begun to engage the pin 97, i. e. the infinitely variable part has reached its lowest transmission ratio. At the same time the gear segment |24, as shown in Fig. 3, engages with the gear |22, whereby the threaded rod and therewith the hollow shaft l I3 is displaced by means of the shifting fork l towards the right. |lhereby the gears llll and Il@ are disengaged and the gears |l2 and H5 engaged. The position of the gears is in such a manner, that during the displacement the gears |03 and ||0 and the gears ||2 and ||5, both pairs are temporarily engaged at the same time, the ratio through the by-pass system and the normal driving system being equal. Therefore the power transmission will not be interrupted. In continuing the rotation of the control shaft |25, then, when the pair of gears |06 and I0 are entirely disengaged, and the power transmission is obtained through the gears ||9, IIB, H5, ||2, the infinitely variable part 9| will be suddenly returned to its highest transmission ratio due to the action of the steep curve |28, on the cam on the pin 91. Whilst the pin 91 slides over the cylindrical portion |3| the gear ||2 vwill mesh with gear |09 simultaneously with gear H5. In continuing the rotation of the control shaft the gears ||2 and ||5 are first disengaged and then also the gear segment |24 from the gear |22. Now the curved portion |21 of the cam occupies the position below the adjustable pin 91. The drive is obtained through the gears |02, |03, |09, ||2 and the speed variation continues in an infinitely variable manner until the cylindrical cam section |29 occupies the position below the adjustable pin 91. Now the other gear segment |24 will be engaged and a further displacement of the hollow shaft ||3 begun, towards the right. Thereby the gears and will be engaged and a little later the gears |09 and ||2 disengaged. Now the sudden return movement of the infinitely variable part is again obtained and subsequently the gear will be engaged with the gear |08 and shortly afterwards disengaged with the gear H6. Now the variation of the speed without change gear stages may be again continued.

Figs. la, 2a, 3a show the drive according to a first engagement, i. e., after the control shaft |25 has been turned counter clockwise for 45. During this engagement the control member 91 of the fluid drive was not moved at rst, since it was then on section |29 of cam |21a, which describes an arc around the shaft axis. Gear |22 was turned by gear segment |24 so that the hollow shaft ||3 was moved to the right. Thus gear ||2 executed rst the meshing with gear ||5 and only after this ntermeshing has been partly affected as gear has been disengaged from gear |06.

During this process the hollow shaft ||3 and with it the driven shaft ||4 has been driven as well over the uid drive 9| with drive shaft |01 as also over the by-pass shaft ||1. The power flow of the -drive has thus not been interrupted during the change-over. After the hollow shaft ||3 had been displaced so far to the right that the ntermeshing of gear ||0 and the gear |05 had been eliminated the steep section |28 of cam I 21a reached control member 91 of the fluid drive 9| and controlled the latter in such'a way that the fluid drive was thereby suddenly returned to the other end of its control area.

With further turning of control shaft |25 section |31 of cam |21a will guide control member 91 without changing the fluid drive transmission ratio, since section |3| forms an ar around the control shaft |25. During this time, segment |24 will bring into engagement gear ||2 and gear |09 and it will engage the latter before it has released its engagement with gear |I of the by-pass shaft I1.

Temporarily the driven shaft ||4 is driven simultaneously by gear ||5 and gear |09 so that the power flow does not suffer any ntBTTuPl'fQIL The complete engagement of gear ||2 with gear |99 will be affected when control shaft |25 will be turned Upon further turning of the control shaft I25 section |21 will affect control member 91 and control it to vary the transmission ratio while the gear drive is not affected since neither of the two gear segments |24 can affect gear |22.

I claim:

1. A power transmission system comprising: a driving shaft; a driven shaft carrying gears; a countershaft, driven from said driving shaft, carrying gears engageable with said gears carried by said driven shaft; a variable speed fluid drive unit driven from said driving shaft and provided with a power take-off shaft carrying gears engagea-ble with said gears carried by said driven shaft; and control means for varying the speed of said power take-off shaft and for selectively engaging and disengaging said countershaft carried gears and driven shaft carried gears and said power take-off shaft carried gears with said driven shaft carried gears, the gears carried by said driven shaft, countershaft and power takeoff shaft being so arranged that pairs of countershaft and driven shaft carried gears and pairs of power take-olf shaft and driven shaft carried gears are initially conjointly in mesh during selective engagement and disengagement.

2. A power transmission system comprising: a driving shaft; a driven shaft carrying gears; a countershaft, driven from said driving shaft, carrying gears engageable with gears carried by said driven shaft to provide different transmission ratios between said driving and said driven shafts; a variable speed fluid drive unit driven from said driving shaft; a power take-off shaft, for said fluid drive unit, carrying gears engageable with said gears carried by said driven shaft to provide different transmission ratios between said power take-off and said driven shafts; and control means for varying the transmission ratio of said fluid drive unit and thereby the speed of said power take-off shaft over a range at least as large as the greatest step-jump between the gears carried by said power take-off shaft and the gears carried by said driven shaft and for selectively engaging and disengaging said driven shaft carried gears and said countershaft carried gears and said power take-off carriedL gears and said driven shaft gears, the gears carried by said driven shaft, countershaft and power take-off shaft being so arranged that pairs of countershaft and driven shaft carried gears and pairs of power take-off shaft and driven shaft carried gears are initially conjointly in mesh during selective engagement and disengagement.

3. A power transmission system comprising: a driving shaft; a driven shaft carrying gears; a countershaft, driven from said driving shaft, carrying gears spaced longitudinally along the axis of said countershaft and engageable with the gears carried by said driven shaft to provide different transmission ratios between said driving and said driven shaft; a variable speed fluid drive unit driven from said driving shaft; a power takeoif shaft, for said fluid drive unit, carrying gears spaced longitudinally along the axis of said power take-off shaft and engageable with said driven shaft carried gears to provide different transmission ratios between said pow-er take-olf and said driven shafts; and control means for varying the transmission ratio of said fluid drive unit and thereby the speed of said power take-oir shaft over a range at least as large as the greatest step-jump between the gears carried by said power take-off shaft and the gears carried by said driven shaft and for selectively engaging and disengaging the driven shaft carried gears with the countershaft carried gears and the power take-off shaft carried gears, the gears carried by said driven shaft, countershaft and power take-off shaft being so arranged that pairs of countershaft and driven shaft carried gears and pairs of power take-off shaft and driven shaft carried gears are initially conjointly in -mesh during selective engagement and disengagement.

4. A power transmission system comprising: a driving shaft; a driven shaft; a countershaft, driven from said driving shaft, carrying gears spaced longitudinally along the axis of said countershaft; a variable speed hydrostatic fluid drive unit driven from said driving shaft; a power take-off shaft, for said fluid drive unit, carrying gears spaced longitudinally along the axis of said shaft; a movable power shaft driving said driven shaft and carrying gears spaced longitudinally along the axis of said power shaft and selectively engageable and disengageable with the countershaft carried gears and the power take-off shaft carried gears, the gears carried by said countershaft, power take-off shaft and power shaft being so arranged that pairs of countershaft and power shaft carried gears and pairs of power take-off shaft and power shaft carried gears are initially conjointly in mesh during selective engagement and disengagement; means for moving said power shaft axially to thereby selectively engage the power shaft carried gears with either the countershaft carried gears or the power take-off shaft carried gears; and control means for varying the transmission ratio of said uicl drive unit and thereby the speed of said power take-off shaft.

5. A power transmission system comprising: a driving shaft; a driven shaft; a countershaft. driven from said Idriving shaft, carrying gears spaced longitudinally along the axis thereof; a variable speed hydrostatic fluid drive unit driven from said driving shaft; a power take-off shaft for said fluid drive unit carrying gears spaced longitudinally along the axis thereof; a hollow power shaft concentric with said driven shaft and carrying gears selectively engageable and disengageable with the countershaft carried gears and the power take-off shaft carried gears, the gears carried by said countershaft, power takeoff shaft and power shaft being so arranged that pairs of countershaft and power shaft carried gears and pairs of power take-off shaft and power shaft carried gears are initially conjointly in mesh during selective engagement and disengagement; means located between said hollow power shaft and said Idriven shaft for driving said driven shaft from said pow-er shaft; control means for moving said hollow power shaft axially, said control means including a movable threaded intermediate shaft and means for moving said power shaft axially in response to movement of said threaded shaft; and means for varying the transmission ratio of said fluid Idrive unit and thereby the speed of said power take-off shaft.

6. A power transmission system according to claim 5 including means to synchronize the positioning of the hollow power shaft with the varying of the transmission ratio of the fiuid drive unit.

7. A power transmission system according! to claim 5 wherein the fluid drive unit is driven from the driving shaft by a hollow input shaft and the power take-off shaft is also hollow to form conduits for the flow of liquid to said fluid drive unit.

EDWARD WOYDT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,178,356 Brunner Oct. 31, 1939 2,213,342 Gossler Sept. 3, 1940 2,241,764 Bollinger et a1. May 13, 1941 2,505,842 Sinclair May 2, 1950 FOREIGN PATENTS Number Country Date 243,182 Switzerland June 30, 1946 873,219 France July 2, 1942 885,427 France Sept. 14, 1943 

